鹿児島大学リポジトリ

Lowering Rate of Freshness and Relative

Thermo-stabilities of Actomyosin-ATPase of

Muscles of Some Fish from Amami Island Sea

著者

NISHIMOTO Jun-ichi, ELOMINA Rene L., MIKI

Hidemasa

journal or

publication title

鹿児島大学水産学部紀要=Memoirs of Faculty of

Fisheries Kagoshima University

volume

30

page range

405-409

別言語のタイトル

奄美大島産魚類筋肉の鮮度低下速度およびアクトミ

オシンATPaseの温度安定性

Vol. 30 pp. 405-409 (1981)

Lowering Rate of Freshness and Relative Thermo

stabilities of Actomyosin-ATPase of Muscles of

Some Fish from Amami Island Sea

Jun-ichi Nishimoto*, Rene L. Elomina* and Hidemasa Miki*

Abstract

To determine the freshness qualities of fish caught from the fishing grounds of Amami Island, the fishK-values at 0, 10,20 and 30°C,and alsothe thermo-stabilities of the actomyosin-ATPase at 20, 25, 30, 35 and 40°C were monitored.

The rate constant (K/) of the decrease in the remaining K-values washighestin Yumekasago>

Sokohobo>Mahata>Sokodara>Ohmonhata>Ohhime at low temperatures. On the other

hand, the first order rate constant (Ad) of the inactivation of actomyosin-ATPase was highest

in Sokohobo at 30°C. The actomyosin of Mahata and Ohhime appeared to be more stable

than Sokohobo, Yumekasago, Sokodara and Ohmonhata.

Compared with frigid water fish at 30°C, the actomyosin of the above sub-tropical fish was

apparently more unstable.

As a key to handling and storage of fish, one fundamental information that must

be known is the inherent capacity of the fish to maintain its freshness at varying

temperatures. Some fish are very sensitive to temperature effect but others have

been noted to deteriorate less even on prolong storage.

Thisproperty can be regarded

as inherent with the fish species1'2) and perhaps may vary with the place of catch,

being of different ambient temperatures. For measurement of freshness of fish,

the degradation of ATP (Adenosine 5'-triphosphate) related compounds (K-value)

coupled with the characteristic actomyosin-ATPase (AM-ATPase) activity are usually

monitored. These information on freshness quality of most common fish such as

mackerel, cod and trout have already been made known, but for others which may

have far economic importance like the fish from sub-tropical sub-deep sea, they are

yet to be reported.

In this regard, this studydealt on the fish coming from the fishing

grounds of Amami Island, a sub-tropical sea north of Ryukyu Island.

Materials and Methods

Sample preparation

Fresh frozen fish from the fishing grounds of Amami Island namely Ohmonhata

(Epinephelus areolatus), Ohhime (Pristipomoides filamentosus), Mahata (Epinephelus

* Laboratory of Food Preservation Science, Faculty of Fisheries, Kagoshima University.

406 Mem. Fac. Fish., Kagoshima Univ. Vol. 30 (1981)

spetemfasciatus), Yumekasago (Helicolemus hilgendorfi), Sokodara (Coryphaenoides sp.),

Sokohobo (Peterygotrigle hemisticta) and Tsumaritsunozame (Squalus megalops) were

placed in —706C freezer and withdrawn on sampling. Anterior dorsal muscles

were ground and used for determination of AM-ATPase activities at 20, 25, and 30°C. Ground whole fish muscles which were kept at 0, 10, 20 and 30°C were used

for determination of K-values.

Chemical analyses

A. K-value3) Muscle perchloric acid extract was chromatographed through Dowex 1x4 (CI", 50-100 mesh) with dilute HC1 and NaCl, and the fractionated nucleotides were read at 250 nm. The K-value was calculated by Saito's formula4). B. AM-ATPase activity The AM solution was prepared using the method of

Takashi et al.5). The solution was incubated at 20, 25 and 30°C and then reacted

with ATP substrate at 25°C for 5 minutes. The liberated phosphorus was measured by Fiske-Sabbrow's method6).

Results and Discussion

Lowering offreshness

The freshness of the fish sample muscle apparently. decreased. with ..time and ..the

logarithm of the decrease, log (100-K), gave characteristically straight lines in all the fish sample muscles. This suggests that the decomposition of ATP and its de

rivatives followed a first order reaction, and as such the deterioration rate constants

(Kf) were calculated accordingly and are shown in Table 1.

Table 1. Rate constants of the decrease in the remaining K-value in the fish sample muscles at various storage temperatures.

Rate constants,/^xlO-^hr-1) Species 0 5 15 25 (°C) Ohhime 0.53 3.78 (154.83) Ohmonhata 1.74 2.50 ( 4.92) ( 9.27) Sokodara 2.15 2.97 4.78 34.27 Mahata 2.73 6.13 ( 29.38) (117.22) Sokohobo 9.14 .14.62 57.39 206.13 Yumekasago 13.77 30.87 54.56 70.76 ( ): Estimated value

Among the 6 species, Yumekasago showed the fastest deterioration rate (highest

Kf), followed by Sokohobo, Mahata, Sokodara, Ohmonhata and Ohhime at low

fast-deteriorating at low keeping temperatures. In fact, they are even faster than known

fast-deteriorating Saba (mackerel) and Hanafuedai2) (Tropidinus ameonus) from Ryukyu

fishing grounds.

Thermostabilities of the AM-A TPase activities

Apparently in Fig. 1, the logarithm of the remaining specific AM-Ca2+-ATPase activities of the samples decreased with incubation period at 20, 25 and 30°C (at 35 and 40°C in the case of shark muscles), and the decrease was greater at higher

temperatures. The plots of log remaining specific AM-Ca2+-ATPase activities with

incubation time were linear with correlation coefficient ranging from 0.9 to 1.0 indicating almost perfect linearity and first-order nature of the reaction. Accordingly, the inactivation rate constants (Kd) were calculated. The first-order rate constants of the inactivation of the AM-ATPase activities evidently increased with temperature (Table 2). The order of their thermo-stabilities at 30°C was as follows: Mahata> Ohhime> Ohmonhata> Sokodara> Yumekasago > Sokohobo.

The thermo-stabilities of the shark muscle AM-Ca2+-ATPase activities however

were higher than any of the samples at 30°C.

Effect of temperature on the inactivation of AM-Ca2+-ATPase in the dorsal muscles of samples

The rates of inactivation of AM-Ca2+-ATPase on incubation for definite periods

Yumekasago w 0 S -2 0 10 20 30 40 0 10 20 30 40 0 10 20 30 40 0 10 20 30 40 Sokodara Time (min.)

Sokohobo Aozame Tsumaritsunozame

X

•\

N.

\ .

\ .

V

0 10 20 30 - 40 0 10 20 30 40 0 10 20 30 40 0 10 20 30 40 Time (min.)

Fig. 1. Logarithm of activities of actomyosin Ca2+-ATPase from the dorsal muscles as a function

of time.

408 Mem. Fac. Fish., Kagoshima Univ. Vol. 30 (1981)

Table 2. Rate constants of the inactivation of actomyosin Ca2+-ATPase from the dorsal muscle of samples in 0.6 M KC1 at various temperatures.

Rate constants (Kd) (X10~4/sec)

20 25 30 35 40 (°C) Ohmonhata 2.4 5.8 13.7 — — Ohhime 1.9 5.2 11.5 — — Mahata 1.7 3.6 8.3 — — Yumekasago 3.9 8.8 17.9 — — Sokodara 2.5 4.0 16.3 — — Sokohobo 2.0 10.1 27.0 — — Aozame — — 1.0 2.1 11.7 Tsumaritsunozame — — 1.1 2.5 12.8

as affected by temperature were measured and their curves are shown in Fig. 2. The temperature at which approximately fifty percent of the ATPase activity was lost within 30 minutes varied among AM of the various fish species. Shark muscles gave high stability even at about 30°C, while Mahata gave at about 27.8°C, Sokodara about 25.6°C, Ohhime about 23.0°C, Ohmonhata about 22.6°C, and Yumekasago

about 20.2°C.

100

30

Temp. ( °C )

Fig, 2. Effect of temperature on inactivation of actomyosin Ca3+-ATPase from the dorsal muscle of samples (pH 6.8 for 30 min).

O: Aozame, A : Tsumaritsunozame, • : Mahata, • : Ohhime, A : Sokodara, • : Ohmonhata, <g): Yumekasago

Many investigators7'8-9) have reported that the thermo-stabilities of the AM or

myofibrils-ATPase prepared from dorsal muscles of epipelagic and mesopelagic and

ofvarious fish species living in the frigid water zone were very unstable.

Comparing

the rate constants and the temperatures of fifty percent reduction in the activity

with representative frigid water fish like Atka mackerel and Alaska pollack, the sub

tropical fish have generally lower values. In other words, the AM of the muscles of Sokohobo, Yumekasago and Sokodara can be said to be more unstable than those of

frigid water fish.

While it has been considered that the thermo-stability of

AM-ATPase in the fish muscle is adapted to the fish environmental temperature7*10), the

finding of this experiment showed otherwise.

For confirmation, it will be necessary to check whether the thermo-stability

ofAM-ATPase of the muscles of the sub-tropical fish samples are more unstable than those

of frigid water fish.

Acknowledgment

This work was supported in part by a special project research fund from the Edu

cation Ministry (Head: Professor Tadao Takahashi, Kagoshima University). The

authors are grateful to Mr. Nakajima for his technical assistance.

References

1) S. Ehira and H. Uchiyama: Bull. Japan. Soc. Sci. Fish., 40, 479-487 (1974). 2) J. Nishimoto and H. Miki: Mem. Fac. Fish., Kagoshima Univ., 28, 65-72 (1979). 3) H. Kobayashi and H. Uchiyama: Bull. Tokai Reg. Fish. Res. Lab., 61, 21-26 (1970). 4) T. Saito, K. Arai and M. Matsuyoshi: Bull. Japan. Soc. Sci. Fish., 24, 749-750 (1959). 5) R. Takashi, K. Arai and T. Saito: Bull. Japan. Soc. Sci. Fish., 36, 169-172 (1970). 6) C. Fiske and Y. Sabbarow: J. Biol. Chem., 66, 375-400 (1925).

7) K. Arai, K. Kawamura and C. Hayashi: Bull. Japan. Soc. Sci. Fish., 39, 1077-1085 (1973).

8) H. Uchiyama, N. Kato, Y. Kudo and K. Arai: Bull. Japan. Soc. Sci. Fish., 44, 491-497 (1978). 9) K. Yabe, K. Nakamura, M. Suzuki and Y. Ito: Bull. Japan. Soc. Sci. Fish., 44, 1345-1350 (1978).